Hypocyclic wheel dresser

ABSTRACT

A diamond tool for dressing a grinding wheel is supported by a fixture for motion along a path having a curvature that can be reversed for generating either a convex or a concave wheel profile, and a radius of curvature that can be increased to infinity for generating a linear profile.

United States Patent Confortiet a1.

[54] HYPOCYCLIC WHEEL DRESSER [72] Inventors: John W. Conforti, Detroit; Joseph Silvagi,

Warren, both of Mich.

[73] Assignee: Camdale Enterprises, Roseville, Mich.

[221 Filed: Aug. 22, 1969 [21] Appl. No.: 852,267

[52] U.S.Cl ..l25/ll AT [51] ..B24b 53/08 [58] Field ofSearch ..l25/11 A, 1lGA;51/90 [56] References Cited UNITED STATES PATENTS 2,197,762 4/1940 Johnson...

Striepe Q: ..125/11 1 1 May 30, 1972 2,301,610 11/1942 Brady ..125/ll 2,401,562 6/1946 Gruenberg.... 1 25/11 2,802,320 8/1957 Nagle ..51/90 X 3,526,060 9/1970 Hall... ...125/l1 X 3,087,284 4/1963 Krott .51/90 2,346,528 4/1944 Websand ..l25/1 1 Primary Examiner-Harold D. Whitehead Attorney-Hauke, Gifiord and Patalidis [5 7] ABSTRACT A diamond tool for dressing a grinding wheel is supported by a fixture for motion along a path having a curvature that can be reversed for generating either a convex or a concave wheel profile, and a radius of curvature that can be increased to infinity for generating a linear profile.

l 1 Claims, 8 Drawing Figures Patented May '30, 1972 3 Sheets-Sheet 1 INVENTORS JOHN w. GOA/FORT! Patented May 30, 1972 3 Sheets-Sheet 2 FIG-5 INVENTORS Fa P mm w, N w .H WW /v N Z w W Patented May 30, 1972 3,665,912

3 Sheets-Sheet 5 -INVENTORS- JOSEPH SILVAGI JOHN W. CONFORTI W 4%? MW HYPOCYCLIC WHEEL DRESSER BACKGROUND OF THE INVENTION This invention relates to tool holders, and more specifically to a holder for supporting a dressing or cutting tool for motion along a path having a selected curvature.

Certain classes of grinding wheels occasionally must be dressed in order to restore the wheel surface to its original shape and accuracy for precision grinding. The dressing is performed by a suitable tool, such as a diamond, which is mounted in a fixture attached to the bed of the grinder.

Most commercial radius dressers support the diamond for motion along a circular path in order to generate either a concave or a convex radius on the grinding wheel periphery, however, they have physical limitations such that for all practical purposes they are incapable of generating a surface having a radius of curvature greater than inches.

SUMMARY OF THE INVENTION -that is one-half that of the ring gear, and is connected,

preferably through a driver gear, the pinion gear a handle such that when the pinion member is rotated about its axis, it rolls along the inner circumference of the ring gear. The ring gear is fixed to a base so that the tool is moved along a path having a component that depends on the pinion gear motion along the ring gear, being in effect a planetary gear motion.

The distance of the tool from the pinion member axis of rotation can be increased or decreased along a radius on which it is mounted. When the cutting edge of the tool is spaced from the pinion member axis a distance equal to the pinion gear pitch radius, it will be fed along a linear path. When this distance is increased, the tool is movable along a substantially circular path. When the distance is decreased, the tool is movably along a substantially circular path having a reversed curvature. Thus, by varying the position of the diamond tool relative to the pinion, it can be disposed for motion along a path having a large radius of curvature, or along a straight line. In addition, the direction of curvature can be easily reversed for generating either concave or convex surfaces.

In a second embodiment, the gear ring is provided with a cylindrical extension adjacent the ring gear teeth, the inner diameter of which forms a race-track having a diameter which is equal to the pitch circle diameter of the ring gear teeth. The pinion is likewise provided with a cylindrical extension forming a disk having an outer diameter equal to the pitch circle diameter of the pinion gear teeth. When the pinion is meshed with the ring gear and rotating relative thereto, the outer diameter of the disk is tightly pressed against the race-track and rotates relative thereto to ensure smoothness and accuracy in operation.

The principles of the invention can be incorporated for supporting other types of cutting tools, such as milling cutters, or single point tools. Still further advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.

DESCRIPTION OF THE DRAWINGS The description refers to the accompanying drawings in which like reference characters refer to like parts and in which:

FIG. 1 is a perspective view showing a preferred wheel dresser mounted on the bed of a grinding machine;

FIG. 2 is an exploded view of the preferred wheel dresser;

LII

FIG. 3 is an elevational view of the preferred wheel dresser with portions of the holder being illustrated in section;

FIGS. 4-6 are schematic diagrams illustrating how the path of the tool varies according to its position with respect to the pinion;

FIG. 7 is an elevational view of another embodiment of a wheel dresser with portions of the holder being illustrated in section; and

FIG. 8 is an exploded view of the wheel dresser illustrated in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, FIG. 1 illustrates a conventional grinding apparatus 10, which has a bed 12 and support structure 14. A grinding wheel 16 is rotatably mounted on the support structure 14 for conventional use in grinding. A preferred wheel dresser, generally indicated at 18, has a diamond tool 20 for dressing the periphery of the grinding wheel 16. For purposes of description, the grinding wheel 16 will be considered as a workpiece for the dressing tool 20.

Referring to FIGS. 2 and 3, the wheel dresser 18 comprises a base 22 adapted for mounting on the bed 12, and a housing 24 which is attached to the base 22. An elongated driver shaft 26 is rotatably mounted in the housing 24. A handle in the form of a knurled knob 28 is secured to one end of the driver shaft 26 and a driver gear 30 is formed on the opposite end of the driver shaft 26. A locking member 32 is mounted on the housing and is received in a recess 34 of the driver shaft 26 when assembled in the housing 24 to lock thedriver shaft 26 against longitudinal displacement.

A ring gear 36, having internal teeth, is secured by threaded fasteners 38 to an enlarged end of the housing 24, with the center of the gear being disposed along the axis of rotation of the driver shaft 24. A pinion member 40 is preferably an integral element having pinion gear teeth 42 meshed with the intemal teeth of the ring gear 36 and driven gear teeth 44 meshed with the teeth of the driver gear 30. The axis of rotation of the pinion member 40 is parallel to the axis of rotation of the driver shaft 24, and the pitch diameter of the pinion gear teeth 42 is one-half that of the pitch diameter of the ring gear 36.

For purposes of illustration, the ring gear 36 is assumed to have 128 internal teeth formed on a pitch circle having a diameter of 4.0 inches, and the pinion member 40 has 64 gear teeth 42 which are assumed to be formed on a pitch circle having a diameter of 2.0 inches. The pinion member 40 has 40 driven gear teeth 44, and the driver gear 30 has 24 teeth.

A cover 46 is slidably mounted over the ring gear 36 to form an enclosure for the gears to protect them from dust and other foreign matter. A retainer 48 is carried on the housing 24 and connected by fasteners 50 to the cover to secure it in position embracing the ring gear 36 as shown. The cover 46 has an opening 52 for joumaling the pinion member 40. The cover 46 and its connected retainer 48 are slidable on the ring gear 36 for moving with the pinion member 40 as it is rolled about the inner circumference of the ring gear 36.

A pin 54 carried by the housing 24 is removably receivable in a bore 55 of the pinion member 40 for selectively locking it in its bottom position. A slide block 56 is bolted to the pinion member 40, being supported on the face of the cover 46, and has a dove-tail shaped tongue 58 on its outer face. A tool holder arm 60, having a dove-tail shaped slot 62, is slidably mounted on the tongue 58. The arm 60 also is slotted inwardly of the slot 62 as at 63 and a set screw fastener 64, carried by the arm 60, provides means for drawing the sides of the slot 62 toward one another for clamping the tongue 58 between them so that the arm 60 is fixedly supported by the slide block 56 in any adjusted position. The diamond tool 20 is carried in a socket 66 at the outer end of the arm 60 and is locked in place by a set screw fastener 68 in the end of the arm 60.

Referring to FIGS. 7 and 8, a wheel dresser, generally indicated at 18' is mounted on a bed 12' and has a diamond tool for dressing the periphery of a grinding wheel 16. The wheel dresser 18' comprises a base 22' having a housing 24 attached thereto. An elongated driver shaft 26' is rotatably mounted within the housing 24'. A handle in the form of a knurled knob 28' is secured to one end of the driver shaft 26 and a driver gear 30 is formed on the opposite end of the driver shaft 26'. A locking member 32' is mounted on the housing 24' and is received in a recess 34 of the driver shaft 26 when assembled in the housing 24' to lock the driver shaft 26' against longitudinal displacement.

A ring gear 36' having internal teeth 37 is secured by threaded fasteners 38 to an enlarged end of the housing 24 with the center of the ring gear 36 being disposed along the axis of rotation of the driver shaft 24'. The ring gear 36 has a cylindrical portion 39 adjacent the internal teeth 37'. The inner surface of the cylindrical portion forms a race-track 41, having an inner diameter which is equal to the pitch circle diameter of the ring gear teeth 37.

A pinion member 40' is preferably an integral element having pinion gear teeth 42' meshed with the internal teeth 37' of the ring gear 36 and driven gear teeth 44' meshed with the teeth of the driver gear 30'. A cylindrical section disposed between gear teeth 42 and the driven gear teeth 44' forms a disk 43' having an outer diameter which is equal to the pitch diameter of the pinion gear teeth 42. When the pinion gear teeth 42' are meshed with the ring gear teeth 37 and rotating relative thereto, the outer diameter of the disk 43 is tightly pressed against the inner diameter of the ring gear race-track 41'. Since there is a minute amount of back-lash between the teeth 42 of the pinion gear and the teeth 37 of the ring gear, the abutting rolling surfaces of the pinion disk 43 against the ring gear race-track 41 ensures smoothness and accuracy in the operation of the device. The axis of rotation of the pinion member 40 is parallel to the axis of rotation of the driver shaft 26' and the pitch diameter of the pinion gear teeth 42' is onehalf that of the pitch diameter of the ring gear teeth 37 Thus, the diameter of the pinion disk 43 will be exactly one-half the diameter of the race-track 41 and upon assembly of the device it can be seen that the pinion disk 43' will be tightly pressed against the surface of the race-track 41.

A cover 46' is slidably mounted over the ring gear 36 and the race-track section 41' to form an enclosure for the gears to protect them from dust and other foreign matter. A retainer ring 48' is carried on the housing 24 and connected by fasteners 50 to the cover to secure it in position embracing the ring gear 36 and race-track section 41 as shown. The cover 46 has an opening 52 for joumalling the pinion member 40'. The cover 46' and its connected retainer ring 48 are slidable on the ring gear 36 for moving with the pinion 40 as the pinion disk 43' is rolled about the inner circumference of the ring gear race-track 41.

A pin 54 carried by the housing 24 is removably receivable in a bore 55' of the pinion member 40 for selectively looking it in its bottom position. A slide block 56 is bolted to the pinion member 40', being supported on the face of the cover 46 and has a dove-tail shaped tongue 58' on the outer face. A tool holder arm 60 having a dove-tail shaped slot 62' is slidably mounted on the tongue 58. The arm 60' also is slotted inwardly of the slot 62 as at 63' and a set screw fastener 64' carried by the arm 60 provides means for drawing the sides of the slot 62' toward one another for clamping the tongue 58' between them so that the arm 60 is fixedly supported by the slide block 56 in any adjusted position. The diamond tool 20 is carried by a socket 66' at the outer end of the arm 60' and is locked in place by a set screw fastener 68 in the end of the arm 60'.

In operation, referring for convenience only to the modification of FIG. 1-3, the user mounts the wheel dresser 18 on the bed 12 and locks the arm 60 on the slide 56 in a tool position that corresponds to the surface configuration that is to be formed on the grinding wheel 16. The pin 54 is removed from the pinion 40, and the user than manipulates the handle 28 in a back and forth motion as the grinding wheel rotates to move the tool 20 across the peripheral edge of the grinding wheel 16 to dress it.

FIGS. 4, 5 and 6 illustrate the relationship between the ring gear 36 and the pinion member 40 that is related to the path of motion of the tool 20. Assuming the large circle 70 represents the pitch circle of the ring gear 36, and the circle 72 represents the pitch circle of the pinion gear teeth 42 as the driven gear 44 is rotated by the driver gear 30, the circle 72 rolls along the inner circumference of the circle 70. Assuming the circle 72 has a diameter D and the circle 70 has a diameter that is twice that of circle 72 or 20, as indicated in FIG. 4, a point on the circle 72 will trace a straight line as the pinion gear teeth 42 roll along the ring gear 36. The slide 56 is mounted on the cover 46 in such a manner that the tool 20 carried by the arm 60 is adjustable along a radius that extends from the axis of rotation A" of the pinion member 40 when located in its bottom position as shown and the axis 8" of the ring gear 36. The axis A" is the center of the circle 72 and the axis 8" is the center of the circle 70.

As shown in FIG. 4, when the cutting tip of the tool 20 is mounted at a distance from the axis A of the pinion member 40 that is equal to the pitch radius of the pinion gear teeth 42, the cutting tip of the tool will move along a straight line L" normal to the A-B radius as the pinion gear teeth 42 roll along the ring gear 36. 7

Referring to FIG. 5, by adjusting the arm 60 to increase the distance between the tip of the tool 20 and the axis A of the pinion member 40, the cutting tip of the tool 20 will move along a curved path to generate a concave surface on the periphery of the grinding wheel 16.

As illustrated in FIG. 6, by adjusting the arm 60 to reduce the distance between the tip of the tool 20 and the axis A," the cutting tip of the tool 20 will be moved along a path having a curvature opposite that associated with the tool position of FIG. 5, to thereby generate a convex surface on the periphery of the grinding wheel 16.

It can be seen that variations in the diameter and shape of the ring gear 36, the pinion member 40 and the driver teeth 30 or the race-track 41' and the pinion disk 43 will provide different shaping paths for the tool 20 to follow, when a special grinding wheel profile is desired. It should also be noted that the path of the tool 20 can be varied by mounting the tool for adjustment along some line other than the herebefore mentioned radius extending between the axis of rotation A of the pinion member 40 and the axis B of the ring gear 36.

It can be seen that the preferred wheel dresser provides means for shaping concave, convex or straight profiles by merely repositioning the arm 60 on the slide 56. The principles of the preferred embodiment can also be employed for mounting other forms of tools, such as a milling cutter or a single point tool, which are to be fed into contact with a workpiece along a path having a large radius of curvature.

Having described our invention, we claim:

1. An apparatus for performing a cutting operation on a workpiece comprising:

a base;

an internal ring gear mounted on said base, said ring gear having a selected pitch circle diameter;

a pinion member having a pinion gear engaging said internal ring gear and rotatable about the inner circumference of said ring gear, said pinion gear having a pitch circle diameter which is equal to one-half the pitch circle diameter of said ring gear;

drive means rotatably carried by said housing about an axis concentric with the axis of said ring gear, said drive means engaging said pinion member to rotate said pinion member about its longitudinal axis in said ring gear and about an axis which is adapted to move along a prescribed arc, and a point on a selected radius of said pinion member defining a predetermined curve as said pinion member moves along said arc,

a cutting tool carried by said pinion member and having a cutting edge adjustable prepositioned to different radii of said pinion member and movable along a selected path determinable by the preposition of said cutting edge relative to said point; and

means mounting said workpiece for engagement with said cutting edge whereby movement of said rotating pinion member along its prescribed arc effects cutting of said workpiece by said cutting edge along said selected path.

2. The apparatus as defined in claim 1, wherein said pinion driving means is adapted to move said pinion member member in a back and forth motion along said prescribed are.

3. The apparatus as defined in claim 1, wherein said ring gear includes a race track having a diameter equal to the pitch circle diameter of said ring gear; and said pinion member includes a disk having a peripheral diameter equal to the pitch circle diameter of said pinion gear, and said pinion member disk rotatably engages said ring gear race track.

4. The apparatus as defined in claim 3, wherein said pinion driving means is adapted to move said pinion disk in a back and forth motion along said prescribed arc.

5. The apparatus as defined in claim 1 wherein said selected radius describes a first circle during rotation of said cutting tool which is interiorly tangential to a second circle concentric to said prescribed arc and twice the diameter of said first circle.

6. The apparatus as defined in claim 1 wherein the cutting edge of said cutting tool is positionable along the selected radius of said point.

7. The apparatus as defined in claim 6 wherein the cutting edge when positioned at said point will move along a straight line on rotation of said tool holder.

8. The apparatus as defined in claim 6 wherein the cutting edge when positioned outwardly of said point from the cutting tool axis will move along a curve generating a concave surface on said workpiece.

9. The apparatus as defined in claim 6 wherein the cutting edge when positioned between said point and said cutting tool axis will move along a curve generating a convex surface on said workpiece.

10. The apparatus defined in claim 1 further comprising means adjustable prepositioning said cutting edge along a radius of said tool holder which may be selectively terminated above, below, or at the axis of said ring gear.

1 1. The apparatus defined in claim 10 wherein said cutting edge on said selected radius of said pinion member defines a curve ranging between hypocycloidal and hypotrochoidal depending upon its position with respect to the axis of said gear ring as said pinion member axis moves along said arc.

. UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 665, 912 C Dated May 30, 1972 Inventor-(5) John W. Conforti et :al (CPI-lO3-A) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

IN THE SPECIFICATION:

Col. 1, line 30, after "gear" delete the pinion gear" and insert --to Col. 1, line 31, delete -"it" and insert therefore -the pinion gear-- Col. 1, line 43, change "movably" to -m ov able-- Col. 3, line 45, delete "ring".

IN THE CLAIMS:

Col. 5, line 8, after "pinion" insert -'-member-- line 9, after "pinion" delete "member" line 17, after "pin-ion" insert -member- Signed and sealed this 7th day of November 1972.

(SEAL) Attest:

EDWARQMLFLETGHER m- ROBERT GOTTSCHALK ttestlng Officer Commissioner of Patents FORM po'mso (10459) USCOMM-DC sows-ps9 U.S, GOVERNMENT PRINTING OFFICE I959 0-366-334 

1. An apparatus for performing a cutting operation on a workpiece comprising: a base; an internal ring gear mounted on said base, said ring gear having a selected pitch circle diameter; a pinion member having a pinion gear engaging said internal ring gear and rotatable about the inner circumference of said ring gear, said pinion gear having a pitch circle diameter which is equal to one-half the pitch circle diameter of said ring gear; drive means rotatably carried by said housing about an axis concentric with the axis of said ring gear, said drive means engaging said pinion member to rotate said pinion member about its longitudinal axis in said ring gear and about an axis which is adapted to move along a prescribed arc, and a point on a selected radius of said pinion member defining a predetermined curve as said pinion member moves along said arc, a cutting tool carried by said pinion member and having a cutting edge adjustable prepositioned to different radii of said pinion member and movable along a selected path determinable by the preposition of said cutting edge relative to said point; and means mounting said workpiece for engagement with said cutting edge whereby movement of said rotating pinion member along its prescribed arc effects cutting of said workpiece by said cutting edge along said selected path.
 2. The apparatus as defined in claim 1, wherein said pinion driving means is adapted to move said pinion member member in a back and forth motion along said prescribed arc.
 3. The apparatus as defined in claim 1, wherein said ring gear includes a race track having a diameter equal to the pitch circle diameter of said ring gear; and said pinion member includes a disk having a peripheral diameter equal to the pitch circle diameter of said pinion gear, and said pinion member disk rotatably engages said ring gear race track.
 4. The apparatus as defined in claim 3, wherein said pinion driving means is adapted to move said pinion disk in a back and forth motion along said prescribed arc.
 5. The apparatus as defined in claim 1 wherein said selected radius describes a first circle during rotation of said cutting tool which is interiorly tangential to a second circle concentric to said prescribed arc and twice the diameter of said first circle.
 6. The apparatus as defined in claim 1 wherein the cutting edge of said cutting tool is positionable along the selected radius of said point.
 7. The apparatus as defined in claim 6 wherein the cutting edge when positioned at said point will move along a straight line on rotation of said tool holder.
 8. The apparatus as defined in claim 6 wherein the cutting edge when positioned outwardly of said point from the cutting tool axis will move along a curve generating a concave surface on said workpiece.
 9. The apparatus as defined in claim 6 wherein the cutting edge when positioned between said point and said cutting tool axis will move along a curve generating a convex surface oN said workpiece.
 10. The apparatus defined in claim 1 further comprising means adjustable prepositioning said cutting edge along a radius of said tool holder which may be selectively terminated above, below, or at the axis of said ring gear.
 11. The apparatus defined in claim 10 wherein said cutting edge on said selected radius of said pinion member defines a curve ranging between hypocycloidal and hypotrochoidal depending upon its position with respect to the axis of said gear ring as said pinion member axis moves along said arc. 